Electrically driven tool compensators are known for moving a tool between a working position and a retracted position in combination with gauging equipment which signals a predetermined increment of tool travel each time tool adjustment is needed. The tool is moveable radially outward and inward in response to axial movements of a draw bar. An electric motor with a gear reducer, drives a screw nut assembly connected to the draw bar so that the draw bar is moved back and forth along the longitudinal axis of the draw bar, where the direction of movement is determined by the direction of rotation of the motor. The nut is formed to a cylindrical shape and has an interior cavity with a threaded opening. The drive nut is slidably mounted within the housing cavity and a draw bar assembly is removably affixed to the nut so that the draw bar moves axially as the nut rotates. A boring bar is conventionally secured to the draw bar and is operable to provide for radially inward and outward movement of a cutting tool. A cam on the boring bar is operated in response to axial movement of the draw bar in one direction to flex a strip member and move the tool radially outwardly toward the workpiece. The amount of adjustment permitted in known tool compensator configurations is less than the degree of movement desired. In particular, if additional movement could be provided more intricate profiles could be cut. Additional movement could also provide more efficient cutting operation, by allowing multiple cuts to be simultaneously performed at different radial positions at the same time. Accuracy, reliability, and repeatability of the positioning movement of the radially moveable body member is also desirable.
The known boring bar configurations can provide radial adjustment of a single cutting tool, or simultaneous adjustment of a plurality of cutting tools. Uneven rates of wear can occur on the cutting edges of a multiple cutter machine tool. Simultaneous radial adjustment of all cutters does not accurately compensate for the differences in rates of wear between the various cutting surfaces. It would be desirable to provide an apparatus for radially adjusting the position of a plurality of tool cartridges individually and independently of one another.